Mr Marshall said it was important in the context of building relations across the island that a northern unionist voice was heard in Dublin.

“I think it’s hugely important that the voices and the opinions are shared,” he told RTE Radio One.

Mr Marshall said he had serious fears for the economy if Brexit happened but he said he was not convinced that the UK would actually leave the European Union.

He said many people in the 2016 referendum voted on the basis of “incorrect and misleading” information.

“The people probably in many cases have a slightly different perspective of this now,” he said.

Mr Marshall added: “I haven’t conceded the fact that we are going to leave – it looks so complex and so difficult at the moment that I believe there is a lot of discussion we still have to have.

“I think If we are truly serious about this that this should possibly go back to the people and the people it will impact most will have the chance to voice their opinion again and I firmly believe if that opportunity arises I think the people will say maybe this isn’t the right idea for the UK to Brexit.”

Sinn Fein president Mary Lou McDonald was among those on hand to congratulate Mr Marshall when his election was announced.

The republican leader had previously insisted the unionist senator would be a welcome addition to the Dail.

“Ian is a unionist. I am an Irish republican,” she said ahead of the vote.

“As I have stated repeatedly, the Ireland I want to see is one where one can comfortably be Irish or British, both or neither. I believe Ian can bring a new and interesting voice to the discussion surrounding a new Ireland.”

The second vacant seat was won by a former Fine Gael TD, Anthony Lawlor.